Applicants claim priority under 35 U.S.C. xc2xa7119 of Canadian Application No. 2, 62,276 filed Feb. 15, 1999. Applicants also claim priority under 35 U.S.C. xc2xa7120 of PCT/CA00/00114 filed Feb. 7, 2000. The international application under PCT article 21 (2) was published in English.
This invention relates to packaging technology, and in particular to an apparatus and method for filing bags with a loose commodity such as seed or grain, by means of an automated apparatus, and carrying the filled bags to a bag sealing station or other processing means.
The bagging of bulk commodities such as seed or grain requires automated equipment for sequentially dispensing a measured quantity or weight of a commodity into an open-topped bag, and transferring the bag to a heat sealing station or other bag-sealing means. Typically in apparatus of this nature, the bulk commodity is dispensed from a hopper into an open-topped bag. After a measured amount is dispensed, the bag is removed from the hopper and discharged from the apparatus. Typically, individual bags are positioned beneath the hopper sequentially. Modern commodity-handling operations require bag filling machines that are capable of operating rapidly and effectively, that is, with a minimum of skipped bags (wherein a bag is missing when the hopper discharges it s load), torn or damaged bags, or doubled-up bags.
Typically, rapidity and precision are achieved by means of an automated device having moveable fingers or other gripping members for manipulation of individual bags before, during and after the filling operation. For example, published Canadian Application 2,091,471 (Huwelmann) discloses a bag-filling apparatus having opposed clamping mechanisms for gripping the open upper end of the bag, and holding the bag open for filling by a hopper or the like. Similarly, U.S. Pat. No. 4,172,349 (Lipes) discloses opening of a bag by means of a pair of opposed gripping members that grip opposing sides of the bag and hold it open at its mouth. A similar arrangement is disclosed in U.S. Pat. No. 4, 651,506 (Lerner et al.).
U.S. Pat. No. 4,124,966 (Wilson) discloses a bag filling apparatus having an overhead hopper and a bag carrying means for positioning the bag in an open-mouth positioned beneath the hopper, and subsequently carrying the filled bag away from the hopper towards a sealing other bag closure means. The bags are gripped initially by a first pair of fingers, which are relatively broad for holding the bag in an open position, and subsequently by a second pair of fingers which are narrow, for pulling opposed ends of the bag away from each other to bring the sides of the bags close to each other, for feeding the bag into a heat seal or the like. This arrangement is complex in that it requires two pairs of moveable fingers, to carry out the separate functions of holding the bag in an open position and subsequently drawing the sides of the bag together. This two-step action makes this arrangement complicated and difficult to operate at the high speeds required of a modem packaging plant.
One requirement is that such apparatus accurately and rapidly transfer individual bags from a bag supply to a filling station and subsequently to a conveyor for transferring the bag to a heat-sealing mechanism or other bag-handling subsystem. This sequence may be efficiently carried out if the bags are transferred efficiently between the various stations.
A further specific requirement that is not adequately addressed in the prior art is for a simple, effective and rapid means whereby empty bags are individually engaged and positioned in an open-topped position to receive a bulk commodity from a hopper or other filling means.
In general terms, it is desirable to provide a simplified yet reliable and speedy mechanism whereby empty bags may be sequentially engaged and transferred in an open position to a bag-filling station, and subsequently transferred to a bag conveyor. Conveniently, the individual bags may be drawn closed as they are being fed to the downstream conveyor. Since typically the downstream conveyor feeds the bags into a heat-sealing station comprising a pair of heated rollers or belts, it is desirable that the mechanism draws the sides of the bags together to form a flattened upper region of the bag to receive a heat seal.
In light of the foregoing, it is an object of the present invention to provide an improved bag filling apparatus and method, whereby individual bags are selectively engaged and positioned for individual filling and subsequently are withdrawn from the filling station in a generally lateral direction for transfer to a downstream conveyor. It is a further object to provide a means whereby the filled bags are generally substantially closed at their upper ends as the bags are transferred to the downstream conveyor, in such a manner as to permit the bags to be conveniently heat sealed at their upper ends.
In accordance with the foregoing objects, the invention comprises in one aspect an apparatus for filling bags with a loose commodity and transferring filled bags to a processing means, of the type comprising:
a bag wicket, a bottom-opening discharge hopper, means for positioning said bags sequentially beneath said hopper and a bag gripping means for closing said bag when filled and displacing said filled bag away from said hopper; said bags having opposed sides and opposed ends. The invention is characterized over the prior art in that the hopper includes a hopper mouth insertable into the bag for holding said bag in an open position during filling;
said bag gripping means comprising a pair of fingers for insertion into an open mouth of said bag at opposed ends thereof, said fingers being independently mounted to moveable support members linked to first reciprocating drive means for driving said support members horizontally in a reciprocating diverging and converging movement, whereby when diverged said fingers grip said bag and draw the opposed sides of said bag together;
second reciprocating drive means to move said fingers vertically to lower said fingers into the open mouth of said bag; and third reciprocating drive means to retract said fingers in tandem horizontally away from said hopper while gripping said bag.
Preferably, the hopper mouth comprises. a pair of reciprocating jaw members which when in a closed position prevent release of said loose commodity, said jaw members being insertable into the mouth of said bag, and which when in an open position release said loose commodity from said hopper while holding open said bag mouth.
The hopper preferably includes drive means for displacing the hopper in a reciprocating vertical motion for insertion of said hopper mouth into said bag mouth for filling the bag and subsequent removal.
Fourth drive means may also be provided for moving said fingers in tandem generally horizontally in a direction transverse to the direction of movement of said third drive means while gripping said bag.
In another aspect, there is further provided a conveyer means for receiving filled bags from said fingers, said conveyer means comprising:
a pair of substantially co-planar rotatable cooperative belt means said belt means mounted for reciprocal converging and diverging movement whereby in a diverged position the belt means are spaced apart from each other to receive said bag, and in a converged position said belt means are sufficiently close together to grip and convey said bag therebetween; and
drive means for rotatably driving at least one of said belts and for actuating at least one of said belt means between said converged and diverged positions.
Preferably, the apparatus further comprises a controller for controlling the apparatus to perform the following sequence of events:
positioning an at least partly opened bag beneath said hopper;
downward movement of said hopper, whereby said jaw members extend at least partly into an open mouth of a first of said bags and deposition of a quantity of said commodity therein;
movement of said moveable fingers laterally towards said hopper means whereby said fingers are positioned substantially over the mouth of said bags;
downward movement of said fingers into said bag;
upward movement of said hopper away from said bag;
diverging movement of said fingers to draw the mouth of said bag taut;
lateral movement of said bag away from said bag wicket thereby removing the filled bag from the wicket and drawing a second bag laterally into position beneath said hopper, and separating said bags; and
transferring said filled bag to a bag sealing station.
In another aspect, the invention comprises:
a method for filling a bag with a loose commodity and transferring said filled bag to a processing means, of the type comprising the steps of:
providing a source of loose commodity;
providing a stacked array of flattened bags on a wicket means and sequentially releasing an individual bag towards said source of loose commodity, said bags each having a mouth, two opposed sides and opposed ends;
sequentially opening said bags and dispensing a selected quantity of said commodity therein;
transferring filled bags away from said source, to a downstream conveyor or processing means.
The invention is characterized over the art by:
providing said bags in an interconnected array;
sequentially withdrawing said filled bags away from said commodity source in a horizontal direction away from said wicket means, while said filled bag is connected to a second empty bag thereby drawing said second of said interconnected bags under said source for filling with said loose commodity; and
subsequently transferring said filled bag in a generally horizontal direction towards said conveyor or downstream processing means.
Preferably said bags are interconnected to form a continuous web by means of generating between the bags a static electrical charge or surface tension for releasably holding neighboring bags together.
Preferably, the step of providing a source of a loose commodity, comprises providing a hopper having an upper region for receiving said loose commodity and a lower region defined by a pair of reciprocating jaws for releasing said loose commodity into the open mouth of a bag;
filling said hopper while said hopper is in a first, elevated position;
lowering said hopper to a second position wherein said jaw extends into the mouth of a bag; and
opening said jaws to dispense said commodity while holding said bag open.
The interconnection of the bags may be achieved by a mechanical interconnection, for example interlocking edge regions of adjacent bags, or surface effects such as surface tension or electrical attraction between contacting bags.
An intermediary conveyor means may receive the filled bags from the transfer mean, to convey the bags by their upper rim to a heat sealing station or the like. The intermediary conveyor may comprise a pair of opposing elongated conveyor members, such as a pair of endless belts driven by pulleys, that diverge to receive a bag and converge to engage and transport the bag.
The step of transferring the filled bag away from the filling station may comprise transferring the filled bag in a first direction for detaching the filled bag from the subsequent bag, and subsequently in a second direction towards the processing means. Alternatively, transfers within the first and second directions may occur essentially simultaneously.
The step of transferring the filled bag may include the step of drawing the open mouth of the bag to a substantially closed configuration, by drawing apart opposed ends of the upper region of the bag, thereby drawing together the opposed sides of the bag, and delivering the substantially closed bag to the processing means.
Having thus described the invention in general terms, the invention will now be further characterized by reference to a description and illustrations of a preferred embodiment.
The directional references employed throughout this specification are in relation to the longitudinal axis of the machine comprising the direction the general direction of movement of the bags subsequent to the filling stage, i.e., from the filling station to the heat sealing station or other downstream processing means.